2G Engine Bearing Replacement as Preventative Maintenance

[kyler021]

Hey all,

I just wanted to know if anyone has replaced rod/main bearings as preventative maintenance? I had a little bit of metal in my oil last oil change ~1300 miles ago, and have been a little worried about that since. I'm about to put a 16g/FMIC/Speed density kit on my car, but there'd be no point in doing all that if I'm just going to spin a bearing soon after. I was thinking I would drop my oil pan before doing the turbo and everything, check the bearings and replace them if needed. I know it's not technically the correct way of doing things, but I just want to squeeze a little more life out of this 200k mile engine.

I know that eventually I need to go through everything. I just want to see A. if the bearings are the cause of the metal, and B. if I can squeeze some more life out of her. Has anyone been in this same situation? If it's a good idea, what size bearings would be okay? Standard size? Oversized?

Thank you guys!
~Kyle

 

[pauleyman]

Hey all,

I just wanted to know if anyone has replaced rod/main bearings as preventative maintenance? I had a little bit of metal in my oil last oil change ~1300 miles ago, and have been a little worried about that since. I'm about to put a 16g/FMIC/Speed density kit on my car, but there'd be no point in doing all that if I'm just going to spin a bearing soon after. I was thinking I would drop my oil pan before doing the turbo and everything, check the bearings and replace them if needed. I know it's not technically the correct way of doing things, but I just want to squeeze a little more life out of this 200k mile engine.

I know that eventually I need to go through everything. I just want to see A. if the bearings are the cause of the metal, and B. if I can squeeze some more life out of her. Has anyone been in this same situation? If it's a good idea, what size bearings would be okay? Standard size? Oversized?

Thank you guys!
~Kyle

Not as preventative maintenance no. You do not use oversized bearings without machine work. People have done what you are suggesting but your comments already stated the obvious. " I know its not technically the correct way". You have to choose what to do. I personally would not. I would inspect and if necessary rebuild.

 

[99dsmer4g63]

Don’t forget you have to do more than just pull the oil pan and slap bearings in it.

-Daniel

 

[chrysler kid]

The short answer is no, these cars are not designed to have engine bearing failure like the bmw designs.

The long answer is to send your oil out for analysis of what is in the oil to determine engine health. Based on the oil analysis they can determine how much metal or metal compounds are circulating in your oil system.

With a good service history and regular checking of fluids these cars should not have bearing failure; however these cars are also known to suffer from crankshaft thrust bearing failure which can eventually damage the crank and prevent uneven wear to the crankshaft and eventually rod bearings. However on properly maintained 4g63 engines with relatively stock clutches this failure has been much rarer than it was when these vehicles were new.

Most of the talks of crank walk (crankshaft thrust bearing failure) in the past were over stated by motors suffering catastrophic failure or heavy duty clutches being incorrectly installed and adjusted

So send your oil out for an analysis

 

[kyler021]

I personally would not. I would inspect and if necessary rebuild.

That's partly what I was thinking as well. Only problem with that is that this isn't a split thrust bearing block, so if I pull the pan see some carnage It'll be on jackstands till I can get a split thrust block somewhere .

The long answer is to send your oil out for analysis of what is in the oil to determine engine health. Based on the oil analysis they can determine how much metal or metal compounds are circulating in your oil system.

This sounds like a good plan I will definitely start there and start researching some places to send my oil out next oil change.

Most of the talks of crank walk (crankshaft thrust bearing failure) in the past were over stated by motors suffering catastrophic failure or heavy duty clutches being incorrectly installed and adjusted

Yep! I haven't popped open the inspection cover to look at the clutch/pressure plate but I'd assume its a stock clutch so I'm hoping to be good there.

Thank you all for your responses!

~Kyle

 

[danl]

Pull the head and look for oil contaminated with glitter in the deep crevices where it likes to collect. Pull the cam caps and look for wear under them. What is your oil pressure on a hot idle? What is the weight of the oil and rpm? Cut apart the oil filter and inspect.

If you see any areas of concern, go further and pull the pan.

 

[kyler021]

Pull the head and look for oil contaminated with glitter in the deep crevices where it likes to collect. Pull the cam caps and look for wear under them. What is your oil pressure on a hot idle? What is the weight of the oil and rpm? Cut apart the oil filter and inspect.

If you see any areas of concern, go further and pull the pan.

So I did an oil change before I refreshed the head, and we cut the filter open and didn't see any metal flakes in the filter media. I also didn't notice anything in the crevices of the head or anything like that. My oil pressure settles around 24-28 psi on an 1100 RPM idle, 10W30 oil. When I do an oil change, I notice some metal on the magnetic drain plug. I don't have a picture of that currently. There was scoring on one of the cam journals, I believe it was the one closest to the cam seal on the exhaust side if I remember correctly. I could grab my fingernail on it pretty easily. I'll post up some pics

The one picture of the drain pan with the filter in it was the most recent one I believe around 1500 miles ago. I'm not sure how well you'll be able to see the metal flakes but I could see them with a flashlight from my phone.

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[SixBolt_16G]

My oil pressure settles around 24-28 psi on an 1100 RPM idle

Off subject, but came across this line and was just curious as to why your idle is set so high. Ive got aggressive cams and im at 1000. Just a knowledge seeking question as I havent come across anyone without cams having an idle that high.

 

[kyler021]

Ive got aggressive cams and im at 1000. Just a knowledge seeking question as I havent come across anyone without cams having an idle that high.

The vibrations at the stock 750 RPM idle were too annoying to me, so I kinda just raised it with DSMLink until it felt smoother. The owner before me deleted the balance shafts, and then I put poly front and rear roll stop mounts which don't help.

I think I may have also been trying to raise the idle to help with my alternator problem, it doesn't charge to 14.5ish volts till about 1400 RPM. I know the fix for that I just haven't gotten around to doing that yet.

 

[BLACK'98DSM]

That is considerable wear to the camshaft. I personally wouldn't want to run that anymore.

 

[kyler021]

That is considerable wear to the camshaft. I personally wouldn't want to run that anymore.

I gotcha. What would you do about the cam/cam cap journal scoring? Would a machine shop be able to machine it flat? Is that even savable? It was pretty deep when I tore it apart, but I didn't measure how deep it went. I probably should have scotch-brite/sanded it down a little bit when it was out to get the high spots down.

 

[BLACK'98DSM]

Have a machine shop take a look for their advice. Sometimes they can machine it out. But something like that, they may want to weld in extra material and do a line bore. Which drives up the cost quite a bit. Or they may suggest a different head casting entirely. It's hard to say personally but that's considerable wear.

 

[danl]

So I did an oil change before I refreshed the head, and we cut the filter open and didn't see any metal flakes in the filter media. I also didn't notice anything in the crevices of the head or anything like that. My oil pressure settles around 24-28 psi on an 1100 RPM idle, 10W30 oil. When I do an oil change, I notice some metal on the magnetic drain plug. I don't have a picture of that currently. There was scoring on one of the cam journals, I believe it was the one closest to the cam seal on the exhaust side if I remember correctly. I could grab my fingernail on it pretty easily. I'll post up some pics

The one picture of the drain pan with the filter in it was the most recent one I believe around 1500 miles ago. I'm not sure how well you'll be able to see the metal flakes but I could see them with a flashlight from my phone.

Whatever is sticking to a magnetic drain plug, it's not bearing because those are not ferrous. That cam looks bad. What was serviced in the head?

 

[kyler021]

But something like that, they may want to weld in extra material and do a line bore. Which drives up the cost quite a bit. Or they may suggest a different head casting entirely. It's hard to say personally but that's considerable wear.

Gotcha I appreciate the insight!

Whatever is sticking to a magnetic drain plug, it's not bearing because those are not ferrous. That cam looks bad. What was serviced in the head?

Ahh I thought bearing was magnetic? Or maybe was it only the gold/copper flakes once you wear through the coating on the bearing? Or maybe I'm just completely wrong. I'm not 100% sure.

The reason I pulled the head was to do a head gasket, because I was leaking oil from the passenger side front corner. While I was in there, I lapped the valves, replaced the head gasket, cam seals, valve seals, ARP head studs and intake manifold gasket. I believe thats everything from what I remember. I did just get a set of exhaust and intake cams from a buddy because I told him what I found during the rebuild. I'm skeptical of throwing those in without fixing the scoring in the head.

 

[danl]

The parts that wear are non ferrous. If you are into the steel backing you would know.

 

[curt-s]

The short answer is no, these cars are not designed to have engine bearing failure like the bmw designs.

The long answer is to send your oil out for analysis of what is in the oil to determine engine health. Based on the oil analysis they can determine how much metal or metal compounds are circulating in your oil system.

With a good service history and regular checking of fluids these cars should not have bearing failure; however these cars are also known to suffer from crankshaft thrust bearing failure which can eventually damage the crank and prevent uneven wear to the crankshaft and eventually rod bearings. However on properly maintained 4g63 engines with relatively stock clutches this failure has been much rarer than it was when these vehicles were new.

Most of the talks of crank walk (crankshaft thrust bearing failure) in the past were over stated by motors suffering catastrophic failure or heavy duty clutches being incorrectly installed and adjusted

So send your oil out for an analysis

I'm willing to bet that misadjusted clutches and people sitting on the clutch at lights are also contributing factors.

 

[jed344]

That cam/ cam journal wear looks bad. Some wear is common but that looks like you can catch your nail on it so i would not continue to run it.

The oil pressure values sound normal for that rpm, but anything that touches oil is contaminated. This means bearings ect. I would not be surprised if there is junk now embedded in the bearings. Generally when we see specs in the oil there is always crap in the bearings too. Last motor we saw this on was due to oil pump gears eating into the front case and we instantly tore it apart. There was pieces in the bearings but we caught it before they where able to tear up the journals so crank was able to just be polished and re used.

I would stop running it and send a oil sample out to blackstone. We have used them before and its very helpful to guide you in what is going on.

 

[danl]

The bad cam bearing supports the timing belt. The oil pump can be damaged if timing belt tension is too high. Oil pump gears are also magnetic. Inspect the oil pump.

 

[chrysler kid]

Having the balance shaft deleted improperly can also cause damage and I assume that magnetic metal debris.

Knowing that I would definitely remove the oil pan and replace the balance shaft delete that is in it, or go even further and remove the oil pump and open it to inspect for further metal debris and damage.